[Boost-commit] svn:boost r61952 - in sandbox/SOC/2010/bit_masks/boost/integer: . details

Subject: [Boost-commit] svn:boost r61952 - in sandbox/SOC/2010/bit_masks/boost/integer: . details
From: bbartmanboost_at_[hidden]
Date: 2010-05-13 12:08:55

Author: bbartman
Date: 2010-05-13 12:08:54 EDT (Thu, 13 May 2010)
New Revision: 61952
URL: http://svn.boost.org/trac/boost/changeset/61952

Log:
working on associating preconditions with bit mask stuff
Text files modified: 
   sandbox/SOC/2010/bit_masks/boost/integer/bit_mask.hpp              |    17 ++++++++--                              
   sandbox/SOC/2010/bit_masks/boost/integer/details/bit_mask_impl.hpp |    61 ++++++--------------------------------- 
   2 files changed, 23 insertions(+), 55 deletions(-)

Modified: sandbox/SOC/2010/bit_masks/boost/integer/bit_mask.hpp
==============================================================================
--- sandbox/SOC/2010/bit_masks/boost/integer/bit_mask.hpp	(original)
+++ sandbox/SOC/2010/bit_masks/boost/integer/bit_mask.hpp	2010-05-13 12:08:54 EDT (Thu, 13 May 2010)
@@ -12,7 +12,7 @@
 // boost dependencies.
 
 
-
+#include <boost/integer/high_low_bits.hpp>
 #include <boost/integer/details/bit_mask_impl.hpp>
 
 namespace boost {
@@ -21,13 +21,22 @@
 /** bit_mask.
  *  Mask which creates a mask give type, offset and width of the mask
  */
-template <typename T, typename Offset, typename Width>
+template <typename T, unsigned int Offset, unsigned int Width = 1 >
 struct bit_mask
-{ };
+    :details::bit_mask_preconditions<T, Offset, Width>,
+    integral_constant<T, (low_bits<T,Width>::value << Offset) >
+{
+    typedef bit_mask<T, Offset, Width> type;
+};
 
+/** Integral Mask.
+ *  This integral Mask is defined similar to an integral constant.
+ */
 template <typename T, T Value>
 struct integral_mask
-{ };
+{
+
+};
 
 } // namespace boost
 

Modified: sandbox/SOC/2010/bit_masks/boost/integer/details/bit_mask_impl.hpp
==============================================================================
--- sandbox/SOC/2010/bit_masks/boost/integer/details/bit_mask_impl.hpp	(original)
+++ sandbox/SOC/2010/bit_masks/boost/integer/details/bit_mask_impl.hpp	2010-05-13 12:08:54 EDT (Thu, 13 May 2010)
@@ -7,35 +7,16 @@
 #ifndef BOOST_BIT_MASK_IMPL_HPP
 #define BOOST_BIT_MASK_IMPL_HPP
 
-#include <boost/mpl/integral_c.hpp>
 #include <boost/type_traits.hpp>
 #include <boost/mpl/bitwise.hpp>
 #include <boost/static_assert.hpp>
+#include <boost/integer/bit_width.hpp>
 
 namespace boost { namespace details {
 
 
 
-/** Type which is used during specialization to infer that a template patameter
- *  has not been used in the initilization of bit_mask_impl.
- */
-struct unused_type { };
-
-/** Forward Declaration for the bit_mask_impl.
- *  This is being used for specifying default parameters so they can be used in 
- *  specializations to see how may parameters bit_mask_impl was called with.
- *  If I had variadic templates this would be less of an issue.
- */
-template <  typename MaskedType,
-            typename MaskOffsetInBits = unused_type ,
-            typename MaskWidth = unused_type >
-struct bit_mask_impl;
-
-
-
-/** Houses the structure for creating simple masks as well as 
- *  implements the preconditions for a simple_bit_mask.
- *
+/** Preconditions for bit_mask impl
  *  Pre-Conditions
  *
  *  1. The width of the masked section must not be longer then the
@@ -47,45 +28,23 @@
  *  
  *  4. The type which is being masked must satisfy the is_integral type trait.
  */
-template <  typename MaskedType,
-            typename MaskOffsetInBits,
-            typename MaskWidth >
-struct bit_mask_impl {
-
+template <typename T, unsigned int Offset, unsigned int Width>
+struct bit_mask_preconditions {
 
     // precondition 1.
-    BOOST_STATIC_ASSERT(( (MaskOffsetInBits::value + MaskWidth::value)
-                            < (sizeof(MaskedType) * 8) ));
+    BOOST_STATIC_ASSERT(( (Offset + Width) < ( bit_width<T>::value - 1)  ));
+
     // precondition 2.
-    BOOST_STATIC_ASSERT(( MaskOffsetInBits::value >= 0 ));
+    // this is always true because the offset is specified as an unsigned integer.
+    // BOOST_STATIC_ASSERT((  >= 0 ));
 
     // precondition 3.
-    BOOST_STATIC_ASSERT(( MaskWidth::value > 0 ));
+    BOOST_STATIC_ASSERT(( Width > 0 ));
     
     // precondition 4.
-    BOOST_STATIC_ASSERT(( is_integral<MaskedType>::value ));
-
-
-    // this is supposed to make decalring a static constant easy, I think...
-    // BOOST_STATIC_CONSTANT( MaskedType, value = ( ) );
-
-    // type typedef
-    typedef bit_mask_impl<   MaskedType,
-                             MaskOffsetInBits,
-                             MaskWidth
-                         >   type;
-
-    typedef MaskedType       mask_type;
-    typedef MaskOffsetInBits bit_offset;
-    typedef MaskWidth        mask_width;
+    BOOST_STATIC_ASSERT(( is_integral<T>::value ));
 };
 
-
-/** bit_mask_impl specialization over an mpl type. */
-template < typename MaskedType, typename IntegralType, IntegralType IntegralValue>
-struct bit_mask_impl< MaskedType, mpl::integral_c<IntegralType, IntegralValue>, unused_type>
-{ };
-
 } // end of details namespace.
 } // end of boost namespace.